Conventionally, in a vehicle door latch device, for example, as described in Patent Literature 1: a latch, a detection lever (a cam in Patent Literature 1), and a detection switch are arranged in a synthetic resin body that is fixed inside a door of a vehicle; a bulged portion bulged out in an axial direction of the latch is integrally formed on a surface of the latch; and rotational positions of the latch, that is, open and closed states of the door, are detected by the detection switch being turned ON and OFF by the bulged portion via the detection lever.